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EOMasters Toolbox Pro | |
A band at a wavelength of 620 is often used for monitoring water
quality, particularly for estimating the concentration of total
suspended solids in inland and coastal waters. Unfortunately, the
Sentinel-2 MSI sensors do not provide data at this wavelength. This
tool uses a polynomial function to estimate data at 620 nm from the
band at 665 nm. This approach is described in 'Estimating the
concentration of total suspended solids in inland and coastal
waters from Sentinel-2 MSI: A semi-analytical approach' by Dalin
Jiang et al.1
There are two ways to create such a band. One in from the Product
Explorer menu to add it to the selected product and the other is an
operator to create a new product and use it in your processing
graph.
The polynomial function has been defined for Sentinel-2 data, but the usage of the tool is not limited to the Sentinel-2. As long as your data has a channel at 665 nm wavelength you can derive the channel at 620 nm. But if you use the tool outside its intended use, you should treat the results with caution.
You can limit the calculation to certain areas of the scene by using an expression, a WKT geometry or a shapefile. Because the polynomial function is only valid for water observations, the results are only reliable for a specific value range. That's why by default, the inputs are limited to the range of 0 to 0.065.
Special for the operator is that you have the choice to create only the 620 nm band or to include also all the source bands.
From the context menu of a product in the Product Explorer you can invoke the action to add the band 620 to the product.
You can invoke the corresponding operator from the main menu at
Optical / Preprocessing / Estimate B620 for S2.